The invention relates to a cylinder head for an internal combustion engine having at least one cylinder, having at least one valve seat ring for a lifting valve, wherein the valve seat ring is surrounded by an annular cooing channel for a coolant which is formed at least partially into the cylinder head, wherein the cooling channel at least partially surrounds the valve seat ring and extends between at least one inlet and at least one outlet.
Known from WO 08/059108 A is a valve seat ring for a piston internal combustion engine disposed in a cylinder head, wherein a circumferential cooling channel is disposed in the valve seat ring, which cooling channel extends between an inlet and an outlet for a coolant.
Present-day high-power internal combustion engines have thermally highly stressed regions, for example in the area of the outlet valve bridges between the outlet valve seats. These regions are particularly vulnerable with respect to thermal deformation and therefore increased valve wear.
WO 2010/145 940 A1 describes a cylinder head for an internal combustion engine with annular cooling channel around outlet valve seat rings, wherein inlets and outlets of the annular cooling channels are disposed diametrically opposite in relation to the axis of the valve seat ring. Similar cooling channels around valve seats are known from DE 34 12 052 A1. These symmetrical cooling measures are however not sufficient to effectively avoid a thermal deformation of the outlet valve bridges in high-power motors.
CH 272 380 8 or GB 668 962 A each describe a valve device of an internal combustion engine with inserted valve seat ring for a poppet valve, wherein the valve seat ring is surrounded by a circumferential cooling channel which extends between an inlet and an outlet. A separating region for the coolant is formed between the inlet and the outlet, which prevents a short circuit flow between inlet and outlet A similar cooling channel has become known from JP 57-015918 U1. This cooling channel arrangement certainly allows an asymmetric cooling of the valve seat rings but the heat removal is inadequate as a result of the low flow rates. It is also disadvantageous that the separating region between inlet and outlet forms an uncooled thermal bridge and as a result, local overheating and thermal stresses can occur, in particular when the separating region is positioned close to the thermally highly loaded web between two outlet valves.
It is the object of the invention to avoid these disadvantages and reduce the valve wear.